Free SEO tool

Readability Checker

Paste your text to get Flesch Reading Ease, Flesch-Kincaid Grade Level and Gunning Fog scores, with the long sentences and complex words that drag them down.

Your Content

How it works

Flesch Reading Ease (FRE)

Developed by Rudolf Flesch in 1948, this formula scores text on a 0 to 100 scale. Higher scores mean easier reading. The formula is: 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words). A score of 60 to 70 is considered standard, easily understood by 13 to 15 year old students. Most web content should aim for 60 or above.

Flesch-Kincaid Grade Level

Created by J. Peter Kincaid for the US Navy, this formula converts readability into a US grade level. The formula is: 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59. A result of 8.0 means the text is suitable for an eighth-grader (13 to 14 years old). For general web content, aim for grade 7 to 9.

Gunning Fog Index

Developed by Robert Gunning in 1952, this index estimates the years of formal education needed to understand a text on first reading. The formula is: 0.4 × ((words ÷ sentences) + 100 × (complex words ÷ words)). “Complex words” are those with three or more syllables, excluding common suffixes like -es, -ed, and -ing. A Fog Index of 12 requires roughly a high-school senior reading level. For most audiences, aim for 8 to 12.

Tips for Better Readability

Keep sentences under 20 words on average.
Use common, everyday words instead of jargon or technical terms.
Break long paragraphs into shorter ones.
Use active voice instead of passive voice.
Front-load your main point in each paragraph.
Read your content aloud. If you stumble, simplify.

About this tool

Readability formulas estimate how much effort a piece of text asks of a reader. They count sentence length and word length, usually by syllables, and turn those counts into a score. Flesch Reading Ease runs from 0 to 100, where a higher score is easier to read. Flesch-Kincaid Grade Level and Gunning Fog express the same idea as a rough number of years of schooling.

I use these scores as a quick editing check, not as a target in themselves. A service page for small business owners usually works best in plain English, while a technical guide can carry longer words if the audience expects them. Search engines do not publish readability scores as a ranking factor, so the reason to improve them is that people understand and act on clearer pages.

Run a draft through the checker, then work on the longest sentences and the densest paragraphs first. Split sentences that carry two ideas, swap jargon for the word a customer would use, and check the score again. Your text stays in your browser and is never uploaded.

How to use it

Paste or type your text into the box.
Read the three scores and the plain-English summary.
Shorten the longest sentences and simplify complex words, then check again.

What it checks

Flesch Reading Ease (0 to 100, higher is easier)
Flesch-Kincaid Grade Level and Gunning Fog Index
Word, sentence and syllable counts behind each score

Limits

Formulas count syllables and sentence length only. They cannot judge accuracy, structure, tone or whether the text answers the reader's question, and syllable counts are estimates.

Frequently asked questions

What is a good Flesch Reading Ease score?

Around 60 to 70 is generally treated as plain English. Specialist audiences can cope with lower scores, so judge it against who will read the page.

Does readability affect Google rankings?

Google has not said it uses readability formulas for ranking. Clearer writing helps people understand the page, which is the outcome that matters.

Is my text uploaded anywhere?

No. The scores are calculated in your browser.

Why do different tools give slightly different scores?

Tools count syllables and sentence breaks in different ways, so small differences between checkers are normal.

If you want a hand making your pages clearer and more persuasive, see my content strategy and briefs service.